Lubricants for reducing corrosion



United States Patent 3,184,411 LUBRTCANTS FOR REDUCXNG CORROSIGN Warren Lowe, Berkeley, Calif., assignor to California Re.

search Corporation, San Francisco, Calif., a corporation of Delaware No Drawing. Filed Sept. 28, 1962, Ser. No. 227,035 5 Claims. (Cl. 25246.7)

This invention pertains to lubricating oil compositions having incorporated therein metal-free detergents. These particular detergents are also effective as corrosion inhibitors.

Present day internal combustion engines operate at high speeds and high compression ratios. When used in the so-called city stop-and-go driving, which includes the greater part of the driving conditions for a large percentage of todays automobiles, the internal combustion engines do not reach the most efiicient operating temperature. Under city driving conditions, large amounts of partial oxidation products are formed, and reach the crankcase of the engine by blowing past the piston rings. This phenomenon is noticed more in engines having greater Wear during the break-in-period. Most of the partial oxidation products are oil-insoluble, tending to form deposits on the various operating parts of the engine, such as the pistons, piston rings, etc. For the purpose of preventing the deposition of these products on the various engine parts and to reduce break-in-wear, it is necessary to incorporate detergents and wear-reducing agents in the lubricating oil compositions, thus keeping these polymeric products dispersed in a condition unfavorable for deposition on metals.

For the most part, the detergents which are added to crankcase oils to reduce this formation of sludges and varnishes are metal organic compounds, particularly those compounds wherein the metal is linked to an organic group through an oxygen atom. Although these metal-containing organic compounds have some effectiveness as detergents for dispersing the precursors of the deposits within the oil itself rather than permitting them to form as deposits on the engine parts, they have the disadvantage of forming ash deposits in the engine. These ash deposits lower engine performance by fouling spark plugs and valves, and contributing to pre-ignition.

It is a particular object of this invention to provide lubricating oil compositions having incorporated therein metal-free detergents which are also effective as corrosion inhibitors. Thus, these new additives disperse the undesirable polymeric products which are formed, and also inhibit corrosion to metal Wearing surfaces.

Therefore, in accordance with this invention, it has been found that lubricating oil compositions particularly useful for heavy duty service are obtained by incorporating therein a product obtained by (1) reacting an alkenyl succinic anhydride and a polyalkylene polyamine, followed by (2) reaction of the product of (l) with phosphorus pentasulfide, that is, P 8

By the use of lubricating oil compositions containing the reaction products described herein, diesel and gasoline engine parts remain remarkably free of deposits and varnish even under severe operating conditions. In addition, these lubricating oils reduce break-in-Wear.

Patented May 18, 1965 The alkenyl succinic anhydrides which are reactants herein are of the formula:

wherein R is a hydrocarbon radical having from 30 to 200 carbon atoms therein, preferably 50 to 200 carbon atoms. Examples of alkenyl radicals include propylene polymers containing from 30 to 200 carbon atoms, and polymers of mixtures of l-butene and isobutene having from 30 to 200 carbon atoms.

The polyalkylene polyamines, which contribute the imide and the basic nitrogen atoms of the reaction products herein, are derived from polymers of ethylene or propylene, such as polyethylene polyamine, and polypropylene polyamines. Such polyalkylene polyamine include those of the formula wherein the R represents the divalent radical ethylene or propylene, and x is a number having a value from 1 to 10 or more.

Examples of polyalkylene polyamines of the above formula include diethylene triamine, triethylene, tetra mine, tetraethylene pentamine, pentaethylene hexamine, dipropylene triamine, dipropylene tetrarnine, tetrapropylene pentarnine, pentapropylene hexamine, di-(trimethylene) triamine, di-(trimethylene) tetramine, tetra-(trirnethylene) pentamine, penta-(trimethylene) hexarnine, etc.

In addition to the above, polyalkylene polyamines include Naminoalkylpiperazine, such as N-aminoethyl piperazine.

The reaction between a polyalkylene polyamine and an alkenyl succinic anhydride can proceed at temperatures ranging from 220 F. to 500 F., preferably from 220 F. to 350 F.

The mol ratio of polyalkylene polyarnine to succinic anhydride can vary from 0.5 :1 to 1:1. Preferably, the polyamine-anhydride mol ratio is 0.8 to 11.

For purposes of simplicity, the product obtained by the reaction of a polyalkylene polyamine and an alkenyl succinic anhydride will be termed a succinimide.

The succinimides herein are reacted with P 8 at temperatures from F. to 400 F., preferably 275 F. to 375 F.

The mol ratio of the P 8 to succinimide can vary from 1:150 to 5:1. Preferably, the mol ratio is in the range of 1:4 to 1:1.

Lubricating oils which can be used as base oils include a Wide variety of lubricating oils, such as naphthenic base, paraffin base, and mixed base lubricating oils, other hydrocarbon lubricants, e.g., lubricating oils derived from coal products, and synthetic oils, e.g., alkylene polymers (such as polymers of propylene, butylene, etc. and the mixtures thereof), alkylene oxide-type polymers (e.g., propylene oxide polymers) and derivatives, including alkylene oxide polymers prepared by polymerizing the alkylene oxide in the presence of water or alcohols, e.g., ethyl alcohol, dicarboxylic acid esters (such as those which are prepared by esterifying such dicarboxylic acids as adipic acid, azelaic acid, suberic acid, sebacic acid, alkanol succinic acid, furnaric acid, maleic acid, etc., with alcohols such as butyl alcohol, hexyl alcohol, 2-ethylhexyl alcohol, dodecyl alcohol, etc.), liquid esters of acids of phosphorus, alkyl benzenes (e.g., monoalkyl benzene such as dodecyl benzene, tetradecyl benzene, etc.), and dialkyl benzenes (e.g., n-nonyl Z-ethyl hexyl benzene); polyphenyls (e.g., biphenyls and terphenyls), alkyl biphenyl ethers, polymers of silicon (e.g., tetraethyl silicate, tetraisopropyl silicates, tetra(4-methyl-2-tetraethy1) silicate, hexyl (4-methyl-2- pentoxy) disiloxane, poly(methyl) siloxane, poly(methylphenyl) siloxane, etc.). Synthetic oils of the alkylene oxide-type polymers which may be used include those exemplified by the alkylene oxide polymers.

The above base oils may be used individually or in combinations thereof, whereever miscible or wherever made so by the use of mutual solvents.

The succinimide P S reaction product described herein can be used in oils of lubricating viscosity in amounts of 0.10% to 40%, by weight, preferably 0.1% to 15%, by weight; more preferably 1% to,

The reaction of an alkenyl succinimide with a polyalkylene polyamine is illustrated in the following examples.

EXAMPLE I Reaction product of tetraethylenepentamine and polybutenyl succinic anhydride A mixture of 84 grams (0.45 mol) of tetraethylene pentarnine and 702 grams (0.45 mol) of a polybutenyl succinic anhydride wherein the polybutenyl radical was derived from a polyisobutene having a molecular weight of about 1,000, was blended with agitation at 125 F. in a nitrogen atmosphere. The temperature was increased to 400 F. during a period of one hour, after which the absolute pressure was reduced to about 200 mm. Hg during a period of 30 minutes to facilitate the removal of water. The reaction mixture was then allowed to reach room temperature at this reduced pressure. The

reaction product contained 5.1% nitrogen.

EXAMPLE II 15.8 pounds of tetraethylenepentamine, blanketed with nitrogen, was heated to 200 F. in a reaction vessel. To

the tetraethylenepentamine was added 262 pounds of 40% mineral oil solution of polyisobutenyl succinic anhydride previously heated to 200 F. The polyisobutenyl radical contained an average of 66 carbon atoms. The whole mixture, blanketed with steam, was heated to a temperature ranging from 310 F. to 320 F. for 30 minutes. The

steam was blown from the mixture by nitrogen. The

nitrogen content of the final oil :blend was 1.78%. The

tetraethylene pentamine-anhydride mol ratio was 0.82.

EXAMPLE III A mixture of 280 grams (0.10 mol) of a 48% mineral oil concentrate of polyisobutenyl succinimide as described in Example II hereinabove and 280 grams of a California EXAMPLE IV A mixture of 240 grams (0.086 mol) of a mineral oil concentrate of the polyisobutenyl succinimide described in Example II hereinabove and 280 grams of a California paraflinic base oil having a viscosity of 150 SSU at 100 F. was heated to ZOO-225 F followed by the slow addition of 4.44 grams (0.02 mol) of P 8 The reaction mixture was heated to 320 F .-350 F. with agitation fo 8 hours, and filtered.

The reaction product contained:

Weight percent Nitrogen 1.8 Phosphorus 0.47 Sulfur 0.46

EXAMPLE V A mixture consisting of 500 grams (0.204 mol) of a 48% oil solution of a polyisobutenyl succinimide as de- 1 Weight percent Phosphorus 2.32

Sulfur 4.59

Table I hereinbelow sets forth data obtained from other numerous reactions between polyisobutenyl succinimides of Example II hereinabove and phosphorus pentasulfide.

TABLE I Reactants, grams Ratio P285 Reaction Compound succinimide Temp., F. time No. P s Succinhours imide 1 2. 22 240 1/8 310-320 5 1. 11 240 1/16 310-320 5 0. 70 280 1/32 250-275 5 0.35 280 1/65 310-320 3 0. 18 280 1/125 310-320 4 2 500 2 Reflux 12 1 48% mineral oil solution.

I 500 grams xylene was used as the reflux solvent.

Table II hereinbelow presents further data on the eflectiveness of the reaction products described herein as lubricating oil additives. The data of Table II were obtained under the severe conditions of a Caterpillar engine test under the MIL-L-45199 procedure. This military specification procedure is so severe that the engine will not even operate with a base oil uncompounded. Even a base oil with the normal commercial additives under this procedure does not provide sufficient lubrication; that is, the engine itself eventually sticks.

The base oil used for the lubricating oil compositions for Table II consisted of a solvent refined SAE 30 oil having incorporated therein 15 mM./kg. of a sulfurized basic calcium phenate, and 12 mM./ kg. of a zinc dialkyl dithiophosphate. The mM./kg. refers to millimols of metal in the finished lubricating oil composition. The succinimide A was the product obtained by first reacting a polyisobutenyl succinic anhydride, wherein the polyisobutenyl radical contained 66 carbon atoms, with a tetraethylene pentamine in a 0.82:1 mol ratio as in Example II hereinabove. succinimide B was the product obtained by reacting succinimide A with P S The PD Nos. refer to the piston discoloration rating. After the engine test, the three piston lands are examined visually. To a piston land which is completely black is assigned a PD No. of 800; to one which is completely clean, a PD No. of 0; to those intermediate between those completely black and completely clean are assigned PD Nos. intermediate in proportion to the extent and degree of darkening.

The GD Nos. refer to the percentage deposit in the piston ring grooves; that is, a 0 evaluation being a clean groove, and a evaluation being a groove full of deposits.

1 PcSa succinimide rnol ratio was 1 1.

Table III hereinbelow presents data showing the eifectiveness of the additives described herein as determined by evaluating a lubricating oil composition in an L-38 Test, using a 1 cylinder CLR engine in a test period of 40 hours. The lubricating oil composition consisted of a California parafiinic base oil having a viscosity of 500 SSU at 100 F., 14 mM./ kg. of a zinc dialkyl dithiophosphate, and 4mM./kg. of a Zinc di-(alkylphenyl) ditbiophosphate, and 3% by weight of the noted succinimide.

TABLE III Succinimide used in Ratio P28 Bearing weight composition sucoinlmide loss (mgm.)

Table IV presents data obtained in an L-38 Strip Crrosion Test. The numbers represent the copper weight loss in milligrams.

The base oil was a California parailinic base oil having a viscosity of 500 SSU at 100 F.

1. A composition of matter comprising a major proportion of an oil of lubricating viscosity, and from 0.10% to 40% by weight of a product obtained by reacting (1) an alkenyl succinic anhydride of the formula R-OH-C wherein R is an alkenyl radical having from 30 to 200 carbon atoms, with a polyalkylene polyamine of the formula wherein R is a divalent radical selected from the group consisting of ethylene and propylene, and x is a number having a value from 1 to 10, the polyamine-anhydride mole ratio being 0.5:1 to 1:1, followed by (2) reacting the product of (1) with phosphorus pentasuhide at temperatures from 70 F. to 400 F, wherein the mole ratio of phosphorus pentasullide to the reaction product of (1) is from 1:32 to 5:1.

2. A composition of matter comprising a major proportion of an oil of lubricating viscosity, and from 0.10%

6 to 40% by weight of a product obtained by reacting (1) an alkenyl succinic anhydride of the formula R-CH-C wherein R is an alkenyl radical having from 30 to 200 carbon atoms, with a polyalkylene polyamine of the formula wherein R is a divalent radical selected from the group consisting of ethylene and propylene, and x is a number having a value from 1 to 10, the polyamine-anhydride mole ratio being 0.5 :1 to 1:1, followed by (2) reacting the product of (l) with phosphorus pentasulfide at temperatures from 275 F. to 375 F., wherein the mole ratio of phosphorus pentasulfide to the reaction product of (-1) is from 1:4 to 1:1.

3. A composition of matter comprising a major proportion of an oil of lubricating viscosity, and from 0.1% to 15% by Weight of a product obtained by reacting (1) an alkenyl succinic anhydride of the formula wherein R is an alkenyl radical having from 30 to 200 carbon atoms, with a polyalkylene polyamine of the formula wherein R is a divalent radical selected from the group consisting of ethylene and propylene, and x is a number having a value from 1 to 10, the polyamine-anhydride mole ratio being 0.5 :1 to 1:1, followed by (2) reacting the product of (1) with phosphorus pentasulfide at tem peratures from 70 F. to 400 F., wherein the mole ratio of phosphorus pentasulfide to the reaction product of ('1) is from 1:32 to 5:1.

4. A composition of matter comprising a major proportion of an oil of lubricating viscosity, and from 0.1% to 10% by weight of a product obtained by reacting (1) an alkenyl succinic anhydride of the formula wherein R is an alkenyl radical having from 30 to 200 carbon atoms, with a polyalkylene polyamine of the formula wherein R is a divalent radical selected from the group consisting of ethylene and propylene, and x is a number having a value from 1 to 10, the polyamine-anhydride mole ratio being 0.5 :1 to 1:1, followed by (2) reacting the product of (1) with phosphorus pentasulfide at term peratnres from 70 F. to 400 F., wherein the mole ratio of phosphorus pentasulfide to the reaction product of (1) is from 1:32 to 5:1.

5. A composition of matter comprising a major proportion of an oil of lubricating viscosity, and from 0.1%

7 v 8 l to 10% by weight of a product obtained by reacting (1) mole ratio being 0.5' :1 to '11, followed by (2) reacting an alkenyl succinic anhydride of the formula the product of (1) with phosphorus pentasulfide at tem- O peratures from 275 F. to 375 F., wherein the mole ratio R OH of phosphorus pentasulfide to the reaction product of (1) 5 is from 1:4 to 1:1.

0 References Cited by the Examiner 0 UNITED STATES PATENTS wherein R is an alkenyl radical having from 30 to 200 10 2,733,235 1/56 Cross et X carbon atoms, with a polyalkylene polyarnine of the 2,773,862 12/56 Mflselman f l 2,977,382 3/61 Millikan 252-32] NHZR'(NHR')XNH2 3,018,247 1/ 62 Anderson et a1. 25232.7

wherein R is a divalent radical selected from the group D ANIEL WYMAN, Primary Examiner consisting of ethylene and propylene, and x is a number 15 having a value from 1 to 10, the polyamine-anhydride ALPHONSO SULLIVAN Examiner- 

1. A COMPOSITION OF MATTER COMPRISING A MAJOR PROPORTION OF AN OIL OF LUBRICATING VISCOSITY, AND FROM 0.10% TO 40% BY WEIGHT OF A PRODUCT OBTAINED BY REACTING (1) AN ALKENYL SUCCINIC ANHYDRIDE OF THE FORMULA 